Using too much water pressure and spraying at too steep of an upward angle can force water behind the siding where it can cause mildew and water damage. Too much pressure sprayed at vinyl siding at an upward angle forces water under the lip of the siding and in through the weep holes of the siding. The weep holes are designed to drain moisture, not large amounts of water. Too much pressure can also leave unsightly wand marks on the siding by removing oxidation; too much water pressure can also crack the siding, knock it loose, or completely blow it off the house.

Cleaning vinyl siding with hot water is also a mistake. Hot water can warp and distort vinyl siding causing it to loosen or pop out of place. Hot water is also very hard on plants and shrubbery and may even damage or kill them. The only benefit to hot water is it can speed up the cleaning process and cut down on the amount of cleaning solution used but the risk isn't worth the reward. The same results are achievable when using cold water and the right cleaners but without the risk of damage to the siding or landscaping that hot water can cause.

Letting the cleaners dry on the house or using the wrong cleaners can cause streaks on the siding. Glass windows can also be damaged or etched by allowing chemicals to dry on them. I highly recommend having a good knowledge of cleaners for washing houses. Some cleaners can not only leave your property damaged but can also cause severe injury to you or others if handled improperly. Always wear the proper protective gear like a respirator, gloves and safety glasses.

Using a pressure washer from a ladder is very dangerous and is not recommended. Serious injury or death can occur. Without the proper equipment, some home owners are tempted to get up on a ladder and attempt to pressure wash their siding. Pulling the trigger on a pressure actuated pump always causes the spray wand to kick and could easily knock you off of a ladder or any elevated platform.

Follow some of these simple DIY tips if you still plan on doing your own pressure washing project.

Ensure that the power washer you are going to use will put out less than 1000 psi. Even most big box store bought machines will put out 2000-2500 psi which can easily damage vinyl siding, asphalt shingles and even wood decks. By changing the nozzle at the end of the gun with one that has a larger orifice, you can achieve a lower pressure. The correct nozzle will still allow the maximum amount of water flow or gallons per minute, which is where your cleaning speed comes from, but will cut back the pressure as to not cause damage to the surface.

Be careful if you're making your own house washing chemicals. For example, mixing bleach and ammonia can create a poisonous gas. We suggest that home owners buy a siding wash that's available in most hardware stores and follow the manufactures guidelines for the product. Leave the stronger agents to the professionals or you may end up doing more damage than good.

Allow the cleaning solution to dwell on the siding for several minutes, then using low pressure, rinse the product from the siding. Make sure when you rinse that you start at the top and work your way down. Also start at one end and work your way across to the other end. Rinse the siding by spraying the water opposite of the laps in the siding so you don't force water behind the it. Do not stop or vary your distance from the siding, or it will cause the surface to be cleaned unevenly. Be sure to rinse the siding and windows thoroughly and to rinse the landscaping before, during and again after the cleaning process to assure no soap is allowed to dry on them.

Following these guidelines and doing some more research can help to eliminate the risk of damage or injury. If you are still unsure of taking on your own pressure washing project, you can call a professional exterior cleaning contractor in your area and see what they can do for you.